• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권9호
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• pp.450-455
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• 2001

We proposed a new sensitivity verification method for the UHF partial discharge(PD) detection system. Initially, we measure the UHF power induced by 5 pC PD which takes place near UHF sensor. Subsequently, we inject the swept UHF signal from a network analyzer into the GIS and measure the attenuation of the signal along the 71S Both the UHF power by 5 pC PD and the attenuation make it possible to verify the sensitivity and spatial coverage of the PD detection system. This method doesn\`t require the calibration of injected pulse type UHF signal into the GIS and makes us precisely measure the attenuation in frequency domain.

• 비파괴검사학회지
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• 제33권2호
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• pp.198-204
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• 2013

리튬이온전지의 충/방전 열화 과정에서 발생하는 음향방출 신호를 검출하여 누적카운트, 방전용량, 미세손상 사이의 상관관계를 확인하였다. 상용 리튬이온전지를 사용하여 가속 충/방전 싸이클 실험을 하면서 음향방출 신호를 수집하였다. 다수의 음향방출 신호가 전지의 충전 및 방전 과정에서 각각 검출되었다. 충/방전 열화 싸이클이 증가함에 따라 전지 용량은 감소하였고 음향방출 신호의 누적카운트는 증가하는 경향을 보였다. 충/방전 후 전지를 분해하여 내부 전극 손상을 관찰한 결과 전극 계면 박리 및 미소균열이 다수 확인되었으며, 이러한 기계적 손상이 음향방출원인 것으로 판단된다. 전지 방전용량과 음향방출 누적카운트 사이에는 선형의 상관관계가 있었으며, 이로부터 음향방출법을 이용한 리튬이온전지 열화 평가 가능성을 제안하였다.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.44-50
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• 2001

현재까지 운전중인 변압기에 전기적인 부분방전 측정기법을 적용하기 위한 가장 큰 문제점은 외부 코로나 노이즈를 제거하는 것이다. 본 논문에서는 외부 코로나 노이즈를 제거하고 변압기 내부의 결함에 의한 부분방전 신호만을 측정하는 기법에 대하여 연구하였다. 현장에서 운전중인 변압기에서의 부분방전과 코로나 노이즈의 발생 형태를 모의하기 위하여 모의 변압기 내에 침-평판 전극을 이용하여 변압기 내부 부분방전을 발생시켰으며, 동시에 변압기 외부의 공기 중에 봉-구 전극을 이용하여 외부 코로나 노이즈를 발생시켰다. 변압기 접지선에 설치한 로고우스키 코일에는 변압기의 내부 결함에 의해 발생되는 부분방전 신호와 외부 코로나 노이즈가 동시에 측정되었다. 변압기 외부에 안테나 센서를 이용하여 외부 코로나 노이즈를 별도로 측정하여, 코로우스키 코일에서 측정된 신호에서 코로나 노이즈를 제거한 결과, 변압기 내부의 부분방전에 의한 신호만을 효과적으로 검출할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.894-899
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• 2002

In this papers, we proposed the new method in order to diagnosis partial discharge type of transformers. For wavelet transform, Daubechies filter is used, we can obtain wavelet coefficients which is used to extract feature of statistical parameters (maximum value, average value, dispersion, skewness, kurtosis) about high frequency current signal per 3-electrode type (needle-plane electrode, IEC electrode and Void electrode.). Also. these coefficients are used to identify Signal of internal partial discharge in transformer. As a result. from compare of high frequency current signal amplitude and average value. we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. otherwise. In case of skewness and kurtosis, we are obtained results of Void electrode> IEC electrode > Needle-Plane electrode. As Improved method in order to diagnosis partial discharge type of transformers, we use neural network.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.217-219
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• 2005

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
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• pp.75-78
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• 2007

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• 정보학연구
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• 제6권1호
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• pp.65-70
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• 2003

본 논문에서 우리는 변압기의 부분방전형태를 진단하기위하여 새로운 방법을 제시하였다. 웨이블렛 변화을 위하여, 다우비치 필터가 사용되어졌다. 우리는 3개의 전극 종류(침대평판자극, IEC전극, 보이드 전극)마다 고주파 전류신호에 관한 통계적인 특징 파라메터(최대값, 평균값, 분산, 왜도, 첨쇄도)를 추출하기위하여 사용하였다. 역시 이들 계수들은 변압기내 내부부분방전의 신호의 정체를 알기위하여 사용되어졌다. 그 결과로서 고주파전류신호의 진폭과 평균값의 비교로부터 우리는 IEC electrode> Void electrode> Needle-Plane electrode의 결과를 얻었다. 반면에 왜도와 첨쇄도의 경우, 우리는 Void electrode> IEC electrode> Needle-Plane electrode을 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
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• pp.211-213
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• 2008

To detect partial discharge of 154kV joint box, we have made experiment by using the Al-foil electrode sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we had used Al-Foil sensor on middle joint box of 154[kV] underground transmission power cable, and then analysed reliability of calibration signal by using the Al-Foil electrode sensor of NJB. From above results, decrement properties measured highly. But incase of injecting calibration signal of 500[pC] after measuring signals in IJB, the S/N ratio had about 25[dB] acquisition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
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• pp.214-217
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• 2008

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding Power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.422-429
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• 2008

This paper presents compact low frequency ultra-wide band (UWB) sensor design and study of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with the newly designed UWB sensor. In this study, we designed a new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both the low frequency and high frequency band of the partial discharge signal. Experiments of offline PD testing on medium voltage (22.9kV) underground cable mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative tests, the calibration signal injection test provided with the conventional IEC 60270 method and high voltage injection testing are included.